Stylus mounting for sound boxes



C. SCRABIC STYLUS MOUNTING FOR SOUND BOXES July 26, 1927. n l 1,636,715

Filed March 28. 19.21

aum/mu,

Patented July 26, 1927i- @cant soltanto, oEiunBANaf'oH'Io."

i' L s'rYLUs MUNTING ron scum)asturias.v

sentation meeuwen 2s, i921. serial 110.456,048,

Thisl invention relates broadlyl to sound reproducing machines, andv has particular` f reference*` to the soundbox 'structures'theref Lof, the primary objectfof the invention being y to provide a soundbox with an improved mounting foreifecting the oscillatory sup port of a cooperative stylus bar, whereby said stylus bar will be properlyfmaintained in engagement with the* diaphragm of the V sound box in order that the vib'ratory movements, imparted to the stylus bar through enga-gement with Arecord grooves, ywill be properly and faithfully transmitted to they diaphragm so as to cause the latter to vi- V brate properlyand in accordance with the sound nundulations phvsically provided in the grooves of a record.

In carrying out theinvention there is employed a sound box which includes a casing v having a vibratableediaphragm mounted therein, the lower port-ion of the casingy being provided with avpairr of spaced brackets between which a stylus .bar is movably trunnioned, the said stylus bar having-its upper end .positively connected with the central portion of the diaphragm, while the lower end of said bar, beneath the pivotal mounting thereof is formed to receive arecord'em gaging needle` a crank` projection being provided upon the stylus bar for cooperation with a `casing carried stationarily mounted spring, the construction and position of the spring being such thatvby vits engagement` with the crank projectiomthe` 'said stylus' "l bar will tend to revolve aboutl its -pivotal mounting so that tension may be maintained,l

between the upper end of said barl and the diaphragm, in order to render thelatter susceptible to the slightest vibratory movements on the part of the stylus bans, l

With these and otherobjects in view, as

will appear as the description proceeds, the

` invention accordingly consists in the novel features of construction, combinations .of

elements and 'arrangements of parts, hereinafter to be fully described andv pointed out y in the appended claims. 'In the accompanying drawing, forming a part of the present disclosure: f

Figure 1 is a vertical lsectional'viewl taken through a sound box and'illustrating the application thereto of the improvedstylus bar mounting comprising the present invention,

Figure 2 is a side elevation, and

Figure 3 is 'a horizontal sectional view taken on the plane In the accompanying drawing the numeral l designates generally'a sound VVbox or reproducer of the'type utilized-inconnection with talking machines, the same being adapted to bersuitably carried by the vouter end of a tone arm 2 'andadapted as usual :tor cooperation with va rotatably carried record, not'shown, fory the purpose of 19e-- producing the sound undulationsfimposed on said record. lIn this instance the sound box includes a casing 3 having a diaphragm chamber 4 provided therein, the said chamber being adapted for .the reception of a vi-` bratable diaphragm 5, the saididiaphragmfis `adapted for cooperation with the stylus bar 6, which is pivotally mountedaas atf7 inconnection with the casingzand-is adapted to be o sclllated, 1n the usual'manner, by coopera; tion with the record `grooves and to transmit the'vibratory movement thereof tothe dia- The present invention concerns itselfmore particularly, in providing an lmproved mounting for the stylusb'ar` in orderthat the latter may be caused to vibrate proper ly, to respondl tothe most minute undulations of a record groove and to cooperate with the diaphragm in such manner thatthe latter will be enabled to reproduce tine tonal shades which are vfrequently, lostin sound reproduction by reason of improperly mounted stylus bars. Y*

` To this'end, the casing 3 has itsfannularA outer wall provided, contiguous to its `lower portion, with .a recess 8, in which isrseatcd a'bracket or plate 9, thelatter being formed to include at its outer vedges a pair of for- .wardly extendingV spaced arms l10, between which the stylus bar 6 is mounted, `The outer ends of the arms l0 are relatively enlarged and are .provided with horizontally extending, registering threaded openings screws have their inner ends formed with conical sockets 13, which are adapted to re- `ceive the sharp pointed. outer yends of a pivot pin-14.LThis pin passes horizontally through the enlarged lower end l5 of thc `stylus bar 6, and is suitably fixed to said stylus bar in order to movey in unison thcrewith.V It will be seen that by properlyadjustlng the screws 12, proper pressure mayk disclosed byy the line i v3**'3 of FigurerQ. f f f 'liu cillate or vibrate freely, i'n a manner which will be characterized by anabsence ofl all undue friction. ment of the bearing screws 12 may be maintained by providing the outer ends of the same'with lock nuts 16, which operate to engage with the sides of the arms and to prevent lossA ofA adjustment on the part of lsaid screws. The lower end 15 of the stylus bar is also formed Awiththe usual-needle `socket 17, in which a needle 18 may be removably` positioned or retained in lsaid socket by means of a set screw- 19. stylus bar, above the portion 15-terminates in a relatively reduced upwardly tapering extremity 20,"which in turn is abruptly terminated in an inwardly vdirected angularly disposed diaphragm engaging portion. 21. This portion extends longitudinally of the axis of said casing and is terminated in physical contact with the louter wall of the diaphragm, a screw or the like 22 being adapted )to positively connect the diaphragm for movement in unison with the upper reduced end of the stylus bar. i

In order to insure proper vibration of the diaphragm in unison and harmony with the sensitively mounted stylus bar, the latter is provided, at a point adjacent to its pivotal support, with an inwardly extendingyintegral crank projection 23, which `is disposed tov occupy a portion of the space between the arms 10. Cooperative rwith this projection 23' is a leaf spring 24, which is carried, in this instance, to be connected with and to lie immediately below the plate 9, the saidspring including a vertically disposed inwardly located finger 25 normally situated to contact with the under surface of the pla-te 9. The finger 25 terminates ina forwardly directed, longitudinally extending portion 26 which, in turn, terminates in ahooked linger 27,'the latter being adapted to contact and vto be maintained constantly in engagement with the under surface of the projection 23. This feature is insured by the provision of a` screw 28, which passesv through an opening provided in a bend 29 provided intermediately in the portion 26` of the spring 24, the inner end of the screw being threaded into an opening provided therefor in the plate 9 or its equivalent. Manifestly, by tightening the screw 28 into frictional engagement with the bend 29 of the spring, the finger 27 will be positively forced into engagement with the projection 23 so as to exercise resilient pressure upon such projection. This results, therefore, in applying such pressure to the stylus bar that the upper end of the latter will tend Furthermore, the adjusti The normally to yswing outwardly and to thereby 'Y result in lplacing av tensionl om the yyconnecf vides a practical, simple and efficient mountl ing for insuring accurate. andproper vibration of the stylus bar of a soundfboxand to properly transmit the oscillation of said stylus bar to an associated diaphragm. f The construction ofthe vmounting by 'reason ofi its simplicity will be reliableandfeective,

and adjustments, Vif required, may be readily effected. The construction 4is such as yto admit of economical manufacture and at the same time to permit of improved soundvreproduction over the ordinary standard constructions now commonly employedf. What is claimed is: Y v

1. In a sound box, a casing, astylusbar pivotally connected to the casing for move-A ment about an axis disposed perpendicularly.

to the major and longitudinal axis; ofpthe stylus bar, said stylus bar being formed'with a horizontally disposed projection extending from the stylus contiguous to itsgpivotal@ mounting and facing towardsai'd casing, a substantially U shaped leaf Aspring having the' opposite arm portions'tlier'eof arranged to engage respectivelyf'said casing and said projection, and a tensioning element. passing through the intermediate portionvlof'fsaid spring and connecting the latter with said casing, one end of said .spring engaging the under'surfa'ce of said projection in order to produce a force tending to 'swing the upper end of the stylus bar in va direction away from said casing.v r

2. In a soundybox, ca casing, a diaphragm mounted within said casing, a stylusbar pivotally connected tothe lower portio'nfof'the casing and having the upperv end' thereof connected to the cent-ral portion`v of the diaphragm, a short offset crank' projection extending rigidly and horizontally from said stylus bar in'substantially Ithe 'plane of the pivotal mounting thereof and facingtoward said casing, a leaf spring ofsubst-antially U shaped configuration including free outer arms, one of said arms engaging thev under surface ofvsaid projection to produce a pres- CARL" soRABrc. 

